In Alpha And Omega, the Heroes actress voices a young female wolf who falls in love with friend Humphrey, voiced by Justin Long - but she must marry a fellow Alpha wolf, while Humphrey is just an Omega.

Hayden, whose boyfriend is 6ft 6in Ukrainian boxer Wladimir Klitschko, is adamant that like the wolves in the movie, we should be free to choose who we fall for.

"I don't think there's any kind of stereotype where you need to be with somebody who does the same job as you, or who's from the same walk of life or looks like you, is the same height as you," she laughed.

"Sometimes you can't help who you fall in love with. And you should be allowed to be with whoever makes you happy."

Hayden also said she was keen not to be typecast when she decided to take on the controversial role of real-life killer Amanda Knox in a new TV film.

She admitted: "I definitely look like a certain type. Having blonde hair and playing a cheerleader a couple of times, it's difficult not to get slotted and be seen as something else.

"It either takes a period of time where the image of this character dies out in people's heads.

"I was incredibly flattered and excited when I got the call and they asked me to play her. I've never played somebody who's a real person, still living and in a very controversial situation, but I'm looking forward to it. It's a really great script."